Maintaining a Swimming Pool's pH Levels

Test the Water

Maintaining a swimming pool's pH levels is important, not only to preserve the pool but also for the health of the swimmers. Check the swimming pool's pH levels at least twice a week using a pH test kit, particularly during the months when the pool sees the most use. The optimum pH level in a swimming pool is from 7.2 to 7.6. If the pH level doesn't fall within that range, the water's pH will need to be adjusted with chemicals. A pH that is too high can cause buildup on the pool's walls and equipment, while a pH that is too low can be corrosive. When adding pH increasers and decreasers to a pool, it's best to use a light hand. It's easier to add more to the pool than try to balance the pH level if too much ends up in the water.

It's more common for a swimming pool's pH level to be too high than too low. The best way to fix this problem is to add a pH decreaser to the water while the pump is running. A muriatic acid solution is frequently used to lower the pool's pH level. When using muriatic acid, look at the packaging to determine how much acid to use (based on pool size). Dilute the muriatic acid with four parts pool water to one part acid, then add it to the deep end of the swimming pool while the pump is running. Wait at least four hours for it to circulate, then retest the water.
Swimming pool supply stores also often sell pH decreasers that are made specifically for this issue. Often, these decreasers are very simple to use, work quickly and come with clear instructions. They're a great alternative to muriatic acid.

When the swimming pool's pH level is too low, a pH increaser should be added to the water to avoid damage to the swimming pool. Though many types of increasers are sold at pool supply stores, a common one is a sodium carbonate-based solution. Consult the directions that come with the pH increaser to determine how much the swimming pool requires. The addition of a sodium carbonate-based pH increaser varies depending on the type of swimming pool and how much the pH needs to rise, so it's best to ask a professional for advice before adding the chemical to the pool. He'll be able to say how much increaser to add and how to add it. As with the pH decreaser, it's important to make sure the pool pump is running when increaser is added to the water. Make sure to test the water after the increaser has time to circulate.